When a subscriber first obtains wireless communications service from a wireless service provider, the wireless service provider assigns a mobile station identification number (MSIN) and a mobile directory number (MDN) to the wireless terminal of the subscriber, wherein the MSIN is a number used by the wireless service provider to uniquely identify the subscriber and/or the wireless terminal, and the MDN is the telephone number of the wireless terminal. If the subscriber thereafter desires to switch to a new wireless service provider, the subscriber must surrender the MDN assigned to its wireless terminal by the old wireless service provider, and be assigned a new MDN by the new wireless service provider. Changing MDNs can be extremely inconvenient, especially if the MDN is used for business. Therefore, it would be convenient if a subscriber could take or "port" a MDN from one wireless service provider to another. In other words, it would be advantageous if a subscriber did not have to change the MDN when he or she switches wireless service providers.
Provisions for porting a mobile directory number are expected to be specified in the well-known ANSI Standard 41. Porting a subscriber's MDN requires the occurrence of at least five distinct events which are not required when the subscriber switches wireless service providers without porting the MDN. First, the new or recipient wireless service provider must inform the old or donor wireless service provider and a Number Portability Administrative Center (NPAC) of the intent to port the subscriber's MDN from the donor wireless provider, wherein the NPAC includes a database for associating subscribers' MDNs to location routing numbers (LRN) identified with wireless service providers currently providing wireless communications service to the subscribers.
Second, Number Portability Databases (NPDB) belonging to wireless service providers (including the recipient and donor wireless service providers) must be updated using the NPAC such that the porting subscriber's MDN is associated with the LRN identifying the recipient wireless service provider. Third, a new Mobile Station Identification Number (MSIN) must be assigned to the subscriber's wireless terminal by the recipient wireless service provider, and a record or entry for the subscriber must be created in a Home Location Register (HLR) belonging to the recipient wireless service provider, wherein the HLR comprises information about subscribers of the wireless service provider to which the HLR belongs, including information associating the newly assigned MSIN to the MDN being ported. Thus, the porting subscriber is now recognized by the recipient wireless service provider as one of its subscribers.
Fourth, the subscriber's wireless terminal must be re-programmed with the new MSIN assigned by the recipient wireless service provider such that the wireless terminal will respond to pages to the new MSIN. And lastly, the subscriber's entry in the donor wireless service provider's HLR must be deleted such that the ported subscriber is no longer a subscriber of the donor wireless service provider.
If all five events do not occur simultaneously, the wireless communication service to the subscriber can be interrupted. For example, if the NPDB is updated before the subscriber's record is created in the recipient wireless service provider's HLR, then a call to the subscriber's wireless terminal may not be completed because the recipient wireless service provider would not recognize the wireless terminal as belonging to one of its subscribers. Likewise, if the NPDB is updated before the subscriber's wireless terminal is re-programmed with the new MSIN from the recipient wireless service provider, then a call to the subscriber's wireless terminal may not be completed because the wireless terminal would not recognize the new MSIN as its own and respond to a page to the new MSIN.
Furthermore, the coordination of these five events is complicated by the fact that the disparate elements are owned and operated by different entities. For example, the donor wireless service provider owns and operates its NPDB and HLR, the recipient wireless service provider owns and operates its NPDB and HLR, and the subscriber owns and operates the wireless terminal. Therefore, a need exists for a method that enables a subscriber's mobile directory number to be ported from a donor wireless service provider to a recipient wireless service provider with minimum interruption to the subscriber's wireless communication service.